DE102020129793A1 - Apparatus and method for die casting metal - Google Patents

Abstract

The invention relates to a device for die casting metal with a casting chamber, a casting cavity and a casting channel, which is designed so that an inner and an outer melt surface can be generated by receiving a melt of the metal in the casting chamber and that between a the inner melt surface acting internal pressure and an external pressure acting on the outer melt surface a pressure difference can be brought about to introduce the melt of the metal from the casting chamber through the casting channel into the casting cavity and that the pressure difference by reducing the internal pressure and / or can be brought about by increasing the external pressure and that to reduce the internal pressure acting on the inner melt surface, a negative pressure can be generated in the casting cavity and / or that to increase the external pressure acting on the outer melt surface, a fluid in the outer volume can be introduced, as well as a method for Druckg pouring of metal.

Description

The invention relates to a device for die casting metal with a casting chamber for receiving a melt of the metal, a casting cavity for hardening the melt of the metal in a defined shape and a casting channel which connects the casting chamber with the casting cavity, and a method for die casting metal.

Die casting is a casting process in which liquid metal is introduced under pressure into a casting cavity in order to solidify there in the shape defined by the casting cavity. Before the melt of the metal reaches the casting cavity, which is also referred to as the casting cavity, the melt is first poured into a casting chamber connected to the casting cavity and pressurized there, for example by a pressure piston. As a result of the pressure acting on the melt stored in the casting chamber, it passes through a casting channel into the casting cavity, so that the desired metal casting is produced there after hardening. With hot chamber die casting, the melt in the casting chamber is also kept warm, which means that the process can be better automated and accelerated. In low-pressure casting, the casting chamber for receiving the molten metal is usually arranged below the casting cavity and the melt is pressurized by compressed air so that the melt rises into the casting cavity against the force of gravity.

The DE 10 2012 010 923 A1 relates, for example, to a conveying device for a melt in a metal casting machine. The conveying device has a storage container for the molten metal and a conveying channel in which the molten metal is fed to a mold cavity. It is provided that the delivery channel comprises a cylinder bore in which a piston is axially adjustable.

The DE 10 2012 009 790 A1 relates to a method in which a liquid metal component is introduced into a cavity by means of a nozzle. It is provided that a transition area between the nozzle and the cavity is cooled after the metal component has been introduced into the cavity in such a way that the metal located in the gate area solidifies. In a later process step, the sprue area is heated again, as a result of which the metal located in the sprue area liquefies again.

A disadvantage of known die-casting processes is that slag forms in the melt over time, which can lead to fluctuations in the filling of the mold or clog the pouring channel. This problem is exacerbated by the use of a pressure piston that moves in the melt. Typically, the melt is also aggressive towards the materials used, such as the crucible and piston. As a result of these problems, reliable sealing of moving parts against one another can also be made more difficult. In low-pressure casting, too, in which the melt is subjected to compressed air, there is always the problem of slag formation. In addition, low-pressure casting has the disadvantage that the melt flow is difficult to dose and control.

The invention is therefore based on the object of specifying a device and a method for die casting in which the formation of slag is avoided or reduced, and which at the same time ensures good metering and control when the melt is introduced into the casting cavity.

According to DIN 8580, die-casting or low-pressure casting are groups of primary forming from the liquid state, e.g. a molten metal. A strict distinction is to be made between the primary molding from the plastic state, e.g. injection molding or transfer molding, especially of plastics.

Against this background, it is also an aspect of the object of the present invention to make the metal die-casting process as reliable and low-maintenance as a plastic injection molding process to a multi-component process with a plastic injection molding component and a metal die-cast component, which forms an efficient composite process. For this purpose, on the one hand - as already stated - the aim is to reduce or avoid the formation of slag and to improve the metering and control of the melt flow in order to keep the maintenance effort of the die casting low. On the other hand, a sprue-free and overflow-free metal die-casting should be made possible in order to avoid a separation of the sprue and overflow before or after an injection molding process step and thus to accelerate and simplify the bonding process.

The object of the invention is achieved by the subjects of the independent claims. Advantageous further developments of the invention are defined in the subclaims.

The invention relates to a device for die casting metal with a casting chamber for receiving a melt of the metal, a casting mold with a casting cavity for hardening the melt of the metal in a defined shape, and a casting channel which the casting chamber with the Casting cavity connects in such a way that the melt of the metal can be introduced from the casting chamber through the casting channel into the casting cavity in order to harden there in the defined shape.

When the casting chamber is sufficiently filled with the molten metal, the melt already partially extends into the casting channel. In other words, the device or its casting chamber or casting channel is designed so that when the melt of the metal is received in the casting chamber, an inner melt surface can be generated which faces inward, i.e. communicates with the casting cavity and an outer melt surface. Surface can be generated that faces outward, that is, communicates with an area referred to as the outer volume.

In order to introduce the melt into the casting cavity, a cylinder or a piston can be used to exert pressure on the outer surface of the melt. In general, however, the device is designed in such a way that a pressure difference can be brought about between an internal pressure acting on the inner melt surface and an external pressure acting on the outer melt surface in order to transfer the melt of the metal from the casting chamber through the casting channel into the casting cavity initiate.

In order to bring about the said pressure difference between the internal and external pressure, the device is designed in such a way that a reduction in the internal pressure acting on the internal melt surface and / or an increase in the external pressure acting on the external melt surface can be brought about. In other words, on the one hand, an active reduction in the internal pressure can take place (without an active change in the external pressure, that is to say with constant or decreasing external pressure). On the other hand, however, an active increase in the external pressure (without an active change in the internal pressure, that is to say with a constant or increasing internal pressure) can also be provided. It is also possible to actively reduce the internal pressure while at the same time actively increasing the external pressure.

Specifically, the device is designed in such a way that, in order to reduce the internal pressure acting on the inner melt surface, a negative pressure can be generated in the casting cavity and / or in the casting channel, in particular the air contained therein or, more generally, the fluid contained therein, can be derived so that the negative pressure relieves pressure on the inner melt surface and / or that a fluid, in particular an incompressible liquid, can be introduced into the outer volume in order to increase the external pressure acting on the outer melt surface, so that the fluid has the outer Melt surface pressurized.

Since, on the one hand, a negative pressure can be actively generated in the casting cavity, the casting cavity can be evacuated gradually so that the metal melt flows through the casting channel into the casting cavity good metering and control of the melt flow is made possible. In particular, due to the possibility of doing without moving parts, the formation of slag can be reduced or avoided. For example, compared to low-pressure casting with an active supply of compressed air from the outside, the melt flow is optimized because there is no increase in the internal pressure when the melt is introduced into the cavity.

Since, on the other hand, the external pressure can be actively increased with a fluid, in particular a liquid, the metal melt can also flow into the casting cavity and, advantageously, moving parts in the melt can be dispensed with (avoidance of slag formation) and good Dosing and control of the melt flow are made possible. For example, compared to low-pressure casting with an active supply of compressed air, metering and control are optimized because an incompressible fluid, in particular a liquid, can be used that can transfer a pressure to the outer melt surface without delay and loss or almost without delay and loss. In addition, the fluid can counteract the formation of slag by sealing off the outer melt surface from undesired contact with oxygen or other substances that promote the formation of slag.

The following alloys in particular come into consideration as molten metal: indium tin eutectic 52ln (48Sn melting temperature approx. 117 ° C), bismuth tin eutectic 58Bi (42Sn melting temperature approx. 138 ° C), tin, tin solder Sn (melting temperature: approx. 180 ° C-232 ° C), as well as other lower or higher melting alloys. The casting chamber (hot chamber device) and / or the casting channel can in particular be heated at least to the melting temperature of the alloy up to approx. 70 ° C. higher. Preferably, all materials in contact with the melt are resistant to the melt (alloying) in order to avoid that the materials used (e.g. metals) dissolve in the melt, the melt is enriched with foreign substances and / or components have to be replaced. The invention enables in particular the avoidance of metallic components (e.g. pistons) in the melt, as a result of which such disadvantageous effects can be avoided.

In a first embodiment of the device for die-casting metal, the Casting cavity has an outlet for pumping out a gas located in the casting cavity in order to generate the negative pressure in the casting cavity, the outlet being arranged in particular at the end of the flow path. The outlet is preferably designed in such a way that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet. This advantageously enables sprueless and overflow-free filling of the cavity, whereby the metal die-casting can be simplified and accelerated, and can thus be as low-maintenance and process-reliable as plastic injection molding.

One way of ensuring that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet is to limit the cross section of the outlet. The cross section is preferably between 0.0001 and 10 square millimeters, particularly preferably between 0.001 and 1 square millimeter. An outlet, for example in the form of a gap or a bore, can for example have a diameter of approximately 0.05 mm to 1 mm. Furthermore, several outlets are also possible, which can in particular be connected in parallel. An outlet can also be formed by a porous area of the casting cavity, e.g. a porous tool insert.

Alternatively or additionally it can be provided that the device comprises a cooling device for cooling the outlet so that the melt of the metal hardens at the outlet so that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet. In other words, active cooling can be provided in the area of the outlet or in the outlet or in the area of a porous insert in order to ensure rapid solidification of the melt. In addition, a material with good thermal conductivity can be used, e.g. with a high copper content. Should the melt nevertheless penetrate the outlet to a minimum, an ejector placed in the outlet can also be provided in order to clean the outlet of any residues of the penetrated melt after each shot.

The first embodiment of the device for die-casting metal can also comprise a vacuum pump, in particular a vacuum pump, which is connected to the outlet of the casting cavity in order to pump off the gas located in the casting cavity through the outlet. A (negative) pressure can in particular be in the range from -1.1 to -0.7 bar, e.g. around -0.9 bar.

In particular with a view to avoiding or reducing slag formation, the first embodiment of the device for die-casting metal can comprise an outer container surrounding the outer volume for receiving a fluid covering the outer melt surface, in particular a gas, in order to seal off the outer melt with oxygen -Surface guarantee. The outer container can accommodate the casting chamber or be formed by it. In particular, it can be provided that a fluid covering the outer melt surface in order to form an oxygen seal does not bring about any active pressurization of the outer melt surface. However, in order to prevent the pressure in the outer container from dropping when the melt is sucked into the casting cavity via a negative pressure, the outer container preferably has an inlet for, in particular passive, subsequent flow of the fluid, in particular the gas, so that a through the Generation of a negative pressure in the casting cavity caused enlargement of the external volume can be compensated for with a constant pressure.

In a second embodiment of the device for die-casting metal, which can be implemented independently of the features of the first embodiment or in combination with features of the first embodiment, the device has an outer container surrounding the outer volume for receiving a fluid covering the outer melt surface , in particular a liquid, in order to apply pressure to the outer melt surface, in particular actively, and preferably at the same time to ensure that the outer melt surface is sealed off with oxygen (avoidance of slag formation). The outer container preferably has an inlet for pumping in (under pressure) the fluid, in particular the liquid, in order to increase the external pressure acting on the outer melt surface by generating an overpressure in the outer container. In the case of an incompressible liquid, there is advantageously no pressure loss here. However, a gas can also be used. In the event that the second embodiment is implemented in combination with the first embodiment, the same outer container can be used to introduce a fluid that, on the one hand, enables oxygen exclusion and, on the other hand, acts as an actively pressurizing medium.

A fluid that is introduced into the outer container, in particular when using a medium to build up pressure, can be designed as an inert medium, in particular one with a lower density than that of the melt. Liquid media are preferably considered, since their incompressibility enables more precise metering of the melt flow. But it is also possible to use gases. In addition, a substance can also be used in a targeted manner as the fluid or a substance can be added to the fluid in a targeted manner which reduces any slag layer on the melt.

An oil, for example, can be used as the fluid that is introduced into the outer container, whereby different oils can be used depending on the alloy being processed (and thus temperature). For example, hydraulic fluids based on phosphate esters or chlorinated aromatics, in particular up to 150 ° C., for example, can be used. Furthermore, silicone oils, for example, can be used, in particular up to approx. 350 ° C. The density of the oil used is preferably in the range from 0.1 to 5 g / cm ³ , preferably in the range from 0.7 to 1 g / cm ³ , so that the density is lower than that of the melt, which, depending on the alloy, is for example Can range from 5 to 7 g / cm ^3. The viscosity of a fluid used, in particular an oil, is preferably in the range from 0.1 to 500 mPAs, more preferably in the range from 0.5 to 100 mPAs, and even more preferably in the range from 1 to 50 mPAs.

The second embodiment of the device for die-casting metal preferably comprises a pressure pump, for example a hydraulic pump or a pneumatic pump, which is connected to the inlet of the outer container in order to pump the fluid pressurizing the outer melt surface, in particular the liquid, into the outer container. The pressure pump is designed in particular to generate at least a pressure of 50 bar, preferably at least 100 bar, particularly preferably at least 150 bar, e.g. approx. 200 bar.

The pressure pump preferably has a pump container for receiving the fluid and a pump piston for pressurizing the fluid in order to pump the fluid into the outer container. Furthermore, the pressure pump preferably has a pressure relief valve for dispensing fluid in order to enable the fluid to be pumped into the outer container under a defined, in particular constant, pressure. The pressure relief valve is preferably designed in such a way that fluid discharged via the pressure relief valve returns to the pump container.

Depending on the fluid that is introduced into the outer container, for example with some oils, the temperature load can essentially act on the part of the fluid that comes into direct contact with the melt, for example if the thermal conductivity of the fluid is in the range from approx 0.15 W / (mK). The device, the casting chamber and / or the outer container can be designed in such a way that convection within the oil is reduced. This has the advantage that further components of the device (in particular the pressure pump or its piston or pressure relief valve) can be operated at or almost at room temperature.

In a third embodiment of the device for die-casting metal, the device is designed in such a way that, on the one hand, a negative pressure can be generated in the casting cavity to reduce the internal pressure acting on the inner melt surface and, on the other hand, to increase the external pressure acting on the outer melt surface Pressure a fluid, in particular a liquid, can be introduced into the external volume. The third embodiment can contain further of the above-described possible additional features of the first and / or the second embodiment.

In particular, the third embodiment can have both an outlet for pumping out a gas located in the casting cavity in order to generate the negative pressure in the casting cavity, as well as an outer container surrounding the outer volume for receiving a fluid, in particular a liquid, covering the outer melt surface, to pressurize the outer melt surface.

Furthermore, the third embodiment can in particular comprise both a vacuum pump, in particular as described above, and a pressure pump, in particular as described above. In this case, the vacuum pump and the pressure pump can preferably be designed as a pump unit. The pump unit can comprise a pump piston which is set up both to pressurize the fluid to be pumped into the outer container and to pump out the gas in the casting cavity, for example in that the piston acts on the front of the pressurized fluid and is connected to the outlet of the casting cavity on the back .

In addition to the device described above, the invention also relates to a method for die casting metal, in particular by means of a device for die casting metal comprising a casting chamber, a casting mold with a casting cavity and a casting channel which connects the casting chamber with the casting cavity, preferably as stated above.

In the method according to the invention, a melt of a metal is introduced into the casting chamber, in particular in such a way that an inner and an outer melt surface is created, the inner melt surface communicating with the casting cavity and the outer melt surface communicating with an external volume.

Furthermore, the melt of the metal is introduced from the casting chamber through the casting channel into the casting cavity, in particular by causing a pressure difference between an internal pressure acting on the inner melt surface and an external pressure acting on the outer melt surface.

Furthermore, the method for die-casting metal can also include further features explained above in the context of the device for die-casting metal.

For example, the pressure difference between the internal pressure and the external pressure is preferably brought about by reducing the internal pressure acting on the inner melt surface by creating a negative pressure in the casting cavity in such a way that the negative pressure relieves pressure on the inner melt surface, so that the melt of the metal flows from the casting chamber through the casting channel into the casting cavity.

Alternatively or cumulatively, the pressure difference between the internal pressure and the external pressure is preferably brought about by increasing the external pressure acting on the external melt surface by introducing a fluid into the external volume in such a way that the fluid pressurizes the external melt surface, so that the melt of the metal flows from the casting chamber through the casting channel into the casting cavity.

In a first variant of the method, the negative pressure in the casting cavity is generated via an outlet for pumping out a gas located in the casting cavity, the outlet preferably being designed in such a way that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet, and the The outlet preferably has a cross section which is between 0.0001 and 10 square millimeters, particularly preferably between 0.001 and 1 square millimeter, so that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet, and the outlet is preferably cooled with it the melt of the metal hardens at the outlet, so that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet.

It can be provided that a fluid, in particular a gas, is introduced into the outer volume in order to ensure that the outer melt surface is sealed off with oxygen, and the fluid, in particular the gas, is preferably allowed to flow into the outer volume, in particular in order to achieve a to compensate for the enlargement of the external volume caused by the generation of a negative pressure in the casting cavity at a constant pressure.

In a second process variant of the process for die casting metal, which can be implemented independently of the features of the first process variant or in combination with features of the first process variant, a fluid, in particular a liquid, is introduced into the outer volume around the outer melt surface to apply pressure and preferably at the same time to ensure an oxygen closure of the outer melt surface, wherein the fluid, in particular the liquid, is preferably pumped into the outer volume in order to increase the external pressure acting on the outer melt surface by generating an overpressure.

The method according to the invention can be used in particular in a multi-component method (composite process) with at least one plastic injection-molded component and at least one metal die-cast component. According to DIN 8580, a distinction is expressly made between the term die-casting, which relates in particular to a molten metal, and the term injection molding, which in contrast relates in particular to a plastic.

In principle, the method according to the invention can initially provide that a component is inserted into the casting cavity before the melt of the metal is introduced into the casting cavity, so that the component is completely or at least partially encapsulated with the melt of the metal. In other words, a method for encapsulating components is also specified in the context of this disclosure.

In particular, in a step preceding the die-casting, the component can be at least partially encapsulated with a plastic, in such a way that a plastic injection-molded component is formed on the component before the component is inserted into the casting cavity. The plastic injection-molded component formed on the component can then be at least partially encapsulated with the melt of the metal in the course of the die-casting, in such a way that a metal-cast component is formed on the plastic injection-molded component.

Optionally, after the plastic injection-molded component formed on the component has been at least partially encapsulated with the melt of the metal, the metal cast component can in turn be at least partially encapsulated with plastic, in such a way that another, in particular one outer, plastic injection molded component is formed.

In a specific application, the component inserted into the casting cavity can be act an electrical connector, wherein the electrical connector comprises one or more line elements that belong to at least one line or at least one connector, and one or more shielding sheaths or shielding housings that belong to at least one line or at least one connector. For further details on the electrical connector, refer to DE 10 2015 102 703 A1 which uses the same nomenclature and which is hereby incorporated by reference.

In the specific application of the method for such a connector it can be provided that the line elements of the electrical connector are at least partially encapsulated with the plastic in order to form a plastic injection-molded component designed as an intermediate insulating body, which the line elements are encapsulated with the melt Metal protects.

Furthermore, it can be provided that the plastic injection-molded component designed as an intermediate insulating body is at least partially encapsulated with the melt of the metal in order to form a metal cast component designed as a shield housing, which either has several shielding shells with one another, or at least one shielding shell with at least one shielding housing , or connects several shielding housings to one another, or forms part of the shielding housing.

In addition, it can be provided that the cast metal component designed as a screen housing is again at least partially encapsulated with plastic, in such a way that an outer plastic injection-molded component is formed on the cast metal component.

• 1 eine erste Ausführungsform einer Vorrichtung zum Druckgießen von Metall,
• 2 eine zweite Ausführungsform einer Vorrichtung zum Druckgießen von Metall,
• 3 eine dritte Ausführungsform einer Vorrichtung zum Druckgießen von Metall,
• 4 drei Verfahrensschritte eines Verbundprozesses mit Spritzgießen und Druckgießen,
• 5 eine kombinierte Spritzguss-Druckguss-Form.

The invention is described in more detail below with reference to the drawings.

• 1 a first embodiment of a device for die casting metal,
• 2 a second embodiment of a device for die casting metal,
• 3rd a third embodiment of a device for die casting metal,
• 4th three process steps of a composite process with injection molding and die casting,
• 5 a combined injection-die-casting mold.

1 Figure 3 shows a first embodiment of a die casting device 10 , also known as a casting unit, with a casting chamber 100 , a two-part mold 301 with a casting cavity located therein 300 and a pouring channel 200 that from the casting chamber 100 to the casting cavity 300 leads.

In the heated casting chamber 100 (Hot chamber) there is a melt of a metal 110 , especially a low-melting metal alloy that is partially in the pouring channel 200 and in it an inner melt surface 120 forms that over the pouring channel 200 with the casting cavity 300 communicates and also an outer melt surface 130 forms that with an external volume 400 communicates.

The casting cavity 300 has an outlet 310 about the that in the casting cavity 300 Any gas located can be pumped out to create a negative pressure in the casting cavity 300 to produce such that the inner melt surface 120 is relieved of pressure and this through the pouring channel 200 into the casting cavity 300 is sucked in. About the negative pressure in the casting cavity 300 to produce is the outlet 310 the casting cavity 300 via a vacuum line 510 with a vacuum pump 500 or connected to a vacuum pump.

In addition, the device comprises 10 one the external volume 400 surrounding outer container 410 for recording a medium 405 , which has a lower density than the melt 110 has, and can serve, the outer melt surface 130 to protect against oxygen and thus counteract the formation of slag. The medium 405 is here via an inlet 420 supplied or can via the inlet 420 flow when the external volume 400 enlarged because the melt 110 into the casting cavity 300 flows in. Basically, it can be the medium 405 but also be about ambient air.

With the application of a vacuum via the vacuum pump 500 there is a pressure difference between that on the inner melt surface 120 acting internal pressure and that on the outer melt surface 130 acting external pressure, so that the casting cavity 300 fills up. In contrast to the conventional low-pressure process, the outer melt surface is used here 130 not through the external medium 405 actively pressurized. Rather, it becomes the inner melt surface 120 actively relieved of pressure. This in the casting cavity 300 increasing melt volume is through the outlet 310 limited. The outlet 310 , is so small that it's in the casting cavity 300 flowing melt 110 not in the outlet 310 can flow in, but arrived there immediately solidified and the outlet 310 locks. In this way, a sprueless and overflow-free casting is made possible, so that the hardened casting can be processed further immediately.

2 Figure 3 shows a second embodiment of a die casting device 10 which in turn have a casting chamber 100 , a pouring channel 200 and a casting cavity 300 disposes. In turn, there is a metal melt in the casting chamber 110 which in this example are already completely in the casting chamber 300 is initiated.

To this end, the device comprises 10 an outer container 410 in the over the inlet 420 on the outer melt surface 130 actively pressurized medium 405 is pumped in. The pressurizing medium 405 is preferably liquid and, for example, in the form of an (almost) inert silicone oil.

Around the pressurized medium 405 in the outer container 410 a pressure pump is used to pump it in 600 used that the medium 405 from a pump container 610 by means of a pump piston 620 into the inlet 420 pumped in. This has the advantage that the movable piston is not in the melt 110 is arranged, but in the medium 405 causing slag formation in the melt 110 is avoided.

In other words, the pressure difference between the inner and the outer melt surface is activated here by the pressure pump designed as a hydraulic pump 600 causes the medium formed as an oil 405 and with it the melt 110 actively pressurizes and into the cavity 300 promoted. In the simplest case, the hydraulic pump can be a piston. Since the medium is preferably incompressible, it can be dosed quite precisely, similar to known methods in which the piston is arranged directly in the melt.

The pressure pump 600 also has a pressure relief valve 630 on what the medium 405 from a pressure threshold value back into the pump tank 610 is left out so that in the outer container 410 this pressure threshold is not exceeded and a reliable, constant application of pressure to the melt 110 is guaranteed. The constant application of pressure is preferably also ensured by the fact that the medium 405 an incompressible liquid is used. With the pressure relief valve 630 becomes, as it were, the pressurizing medium 405 regulated, controlled or diverted. This will keep any moving part within the melt 110 avoided, as can the pressurizing medium 405 also serve as an oxygen seal.

The pressure relief valve 630 also forms an outlet device or a bypass when the cavity is filled 300 the melt volume is limited, and is arranged in the hydraulic circuit, so that the medium designed as hydraulic oil 405 leads back to the hydraulic reservoir in the bypass 610 . With the appropriate arrangement, the entire hydraulic installation can be operated almost at room temperature.

That over the melt 110 located medium 405 , for example an inert oil, can also be used to seal off the melt so that no oxidation processes can take place. Instead of a liquid, however, a gas, for example nitrogen or argon, can also be used in a similar arrangement. Instead of a hydraulic pump, the gas is then preferably taken from a pressure vessel, the bypass can lead into the ambient air or the gas is collected and reused.

3rd Fig. 3 shows a third embodiment of a die casting device 10 combining the first and second embodiments with each other. There is also a pumping unit 550 provided which both the vacuum pump 500 as well as the pressure pump 600 forms. The pump unit thus acts on the one hand on the medium 405 with pressure to in the outer container 410 to increase the pressure on the melt 110 acts, and is at the same time via a vacuum line 510 with the outlet 310 the casting cavity 300 connected to generate a negative pressure therein.

Specifically, the back of the pump piston can do this 620 for generating the negative pressure in the cavity 300 be used. The piston 620 for example, have active surfaces of different sizes in order to convey a larger volume of air, for example to compensate for leaks in the mold separation.

4th shows a three-stage composite process comprising injection molding of plastic and die casting of metal, the terms injection molding and die casting according to DIN 8580 being defined and separated from one another.

In a first step (a) an injection mold is made 301 ' with an injection cavity 300 ' provided and plastic via a spray line 200 ' into the injection mold 301 ' injected. This creates a component with a plastic injection-molded component, which is then inserted into the casting cavity 300 a die-cast mold 301 inserted and in a second step (b) it is cast around with metal by passing through the pouring channel 200 a metal melt, in particular as described above, is introduced, so that a metal casting component is formed. This creates a two-component component, which can optionally be placed in an injection cavity again 300 " another injection mold 301 " can be inserted in order to be overmolded with plastic again.

5 shows a two-part combined injection molding / pressure casting mold 312 with the steps described above can also be carried out. The combined injection-die-casting form 312 comprises a first injection cavity 300 ' a separate casting cavity for curing an injected plastic 300 for hardening a melt of a metal and a separate second injection cavity 300 " for curing an injected plastic.

A multi-component injection-molding-injection process in a compound system can be used, for example, to produce a shield for an electrical connector. First of all, the electrical connector is overmolded in a plastic injection molding process, then immediately afterwards metal is overmolded to produce a shielding, and immediately afterwards again overmolded with plastic injection molding. With the die-casting method according to the invention or the die-casting device according to the invention, the metal casting process can be designed to be as reliable and low-maintenance as a plastic injection molding process or both plastic injection molding processes. As already described above, this is made possible in particular by a sprue-free and also overflow-free die casting, so that no separation of the sprue and overflow is necessary before the subsequent overmolding process. By avoiding the formation of slag in the molten metal, fluctuations in the filling of the mold in the casting process and clogging of the casting channel are avoided, so that the die-casting is low-maintenance.

It is evident to the person skilled in the art that the embodiments described above are to be understood as examples and that the invention is not restricted to them, but can be varied in many ways without departing from the scope of protection of the claims. In particular, the features of the first and second embodiments can be expressly combined with one another. Furthermore, it can be seen that the features, regardless of whether they are disclosed in the description, the claims, the figures or otherwise, also individually define essential components of the invention, even if they are described together with other features.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102012010923 A1 [0003]
• DE 102012009790 A1 [0004]
• DE 102015102703 A1 [0045]

Claims (16)

Apparatus (10) for die casting metal comprising: a casting chamber (100) for receiving a melt (110) of the metal, a casting mold (301) with a casting cavity (300) for hardening the melt (110) of the metal in a defined shape and a casting channel (200) which connects the casting chamber (100) with the casting cavity (300), such that the melt (110) of the metal can be introduced from the casting chamber (100) through the casting channel (200) into the casting cavity (300) in order to to harden there in a defined form, wherein the device is designed such that an inner (120) and an outer (130) melt surface can be generated by receiving the melt (110) of the metal in the casting chamber (100), the inner melt surface (120) with the casting cavity (300) communicates and the outer melt surface (130) communicates with an outer volume (400), and wherein the device is designed in such a way that a pressure difference can be brought about between an internal pressure acting on the inner melt surface (120) and an external pressure acting on the outer melt surface (130) in order to remove the melt (110) of the metal to introduce the casting chamber (100) through the casting channel (200) into the casting cavity (300), and wherein the device is designed such that the pressure difference between the internal pressure and the external pressure by reducing the internal pressure acting on the inner melt surface (120) and / or by increasing the external pressure acting on the outer melt surface (130) Pressure can be brought about, and wherein the device is designed in such a way that, in order to reduce the internal pressure acting on the inner melt surface (120), a negative pressure can be generated in the casting cavity (300) such that the negative pressure relieves pressure (120) on the inner melt surface (120) ) and / or that in order to increase the external pressure acting on the external melt surface (130), a fluid (405) can be introduced into the external volume (400) in such a way that the fluid (405) touches the external melt surface (130) pressurized. Device (10) for die casting metal according to the preceding claim, wherein the casting cavity (300) has an outlet (310) for pumping out a gas located in the casting cavity in order to generate the negative pressure in the casting cavity (300), and wherein the outlet (310) is preferably designed such that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet (310), and wherein the outlet (310) preferably has a cross section which is between 0.0001 and 10 square millimeters, particularly preferably between 0.001 and 1 square millimeter, so that the melt (110) of the metal to be introduced into the casting cavity does not enter the outlet (310) can flow in, and wherein the device preferably comprises a cooling device for cooling the outlet (310) so that the melt (110) of the metal hardens at the outlet (310) so that the melt (110) of the metal to be introduced into the casting cavity does not enter the outlet (310) can flow in. Device for die casting of metal according to the preceding claim, wherein the device further comprises a vacuum pump (500) which is connected to the outlet (310) of the casting cavity (300) to pump the gas in the casting cavity (300) through the outlet ( 310) to be pumped out. Device (10) for die-casting metal according to one of the preceding claims, wherein the device comprises an outer container (410) surrounding the outer volume (400) for receiving a fluid (405) covering the outer melt surface (130), in particular a gas , in order to ensure an oxygen exclusion of the outer melt surface (130), and wherein the outer container (410) preferably comprises an inlet (420) for the subsequent flow of the fluid (405), in particular the gas, in particular in order to create a To compensate for the negative pressure in the casting cavity (300) due to the enlargement of the external volume (400) at a constant pressure. Device (10) for die-casting metal according to one of the preceding claims, wherein the device comprises an outer container (410) surrounding the outer volume (400) for receiving a fluid (405) covering the outer melt surface, in particular a liquid, to which to pressurize the outer melt surface (130) and preferably at the same time ensure an oxygen shut-off of the outer melt surface (130), and the outer container (410) preferably has an inlet (420) for pumping in the fluid (405), in particular the Liquid, comprises in order to increase the external pressure acting on the outer melt surface (130) by generating an overpressure in the outer container (410). Device (10) for die casting of metal according to one of the preceding claims, wherein the device comprises a pressure pump (600) which is connected to the inlet (420) of the outer container in order to circulate the fluid (405) which pressurizes the outer melt surface (130) ), in particular the liquid to be pumped into the outer container (410), and wherein the pressure pump (600) preferably comprises a pump container (610) for receiving the fluid (405) and a pump piston (620) for pressurizing the fluid (405) to the fluid pump into the outer container (410), and wherein the pressure pump (600) preferably comprises a pressure relief valve (630) for dispensing fluid (405) to enable the fluid to be pumped into the outer container under a defined, in particular constant, pressure, and wherein the pressure relief valve (630) is preferably designed in such a way that fluid discharged via the pressure relief valve reaches the pump container (610). Device (10) for die casting metal according to one of the preceding claims, wherein the device includes both a vacuum pump (500), in particular according to Claim 3 , as well as a pressure pump (600), in particular according to Claim 6 , and wherein the vacuum pump (500) and the pressure pump (600) are preferably designed as a pump unit (550), and wherein the pump unit (550) preferably comprises a pump piston, which is used both for pressurizing the fluid (405) to be pumped into the outer container. as well as for pumping out the gas located in the casting cavity (300). Method for die casting metal, in particular by means of a device (10) for die casting metal comprising a casting chamber (100), a casting mold (301) with a casting cavity (300) and a casting channel (200) which the casting chamber (100) with the casting cavity (300) connects, in particular according to one of the Claims 1 to 7th , wherein a melt (110) of a metal is introduced into the casting chamber (100), in particular in such a way that an inner and an outer melt surface is formed, the inner melt surface (120) communicating with the casting cavity and the outer melt Surface (130) communicates with an outer volume (400), and wherein the melt (110) of the metal is introduced from the casting chamber (100) through the casting channel (200) into the casting cavity (300), in particular by being placed on the inner melt -Surface acting internal pressure and an external pressure acting on the outer melt surface, a pressure difference is brought about. Process for die casting metal according to Claim 8 , wherein the pressure difference between the internal pressure and the external pressure is brought about by reducing the internal pressure acting on the inner melt surface (120) by creating a negative pressure in the casting cavity in such a way that the negative pressure relieves pressure on the inner melt surface , so that the melt of the metal flows from the casting chamber through the casting channel into the casting cavity and / or wherein the pressure difference between the internal pressure and the external pressure is brought about by increasing the external pressure acting on the external melt surface (130) by a fluid is introduced into the outer volume in such a way that the fluid pressurizes the outer melt surface, so that the melt of the metal flows from the casting chamber through the casting channel into the casting cavity. Process for die casting metal according to Claim 8 or 9 , wherein the negative pressure in the casting cavity is generated via an outlet (310) for pumping out a gas located in the casting cavity, and wherein the outlet (310) is preferably designed such that the melt of the metal to be introduced into the casting cavity does not flow into the outlet can, and wherein the outlet (310) preferably has a cross section which is between 0.0001 and 10 square millimeters, particularly preferably between 0.001 and 1 square millimeter, so that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet, and wherein the outlet (310) is preferably cooled so that the melt of the metal hardens at the outlet, so that the melt of the metal to be introduced into the casting cavity cannot flow into the outlet. Method for die casting metal according to one of the Claims 8 to 10 , wherein a fluid (405), in particular a gas, is introduced into the outer volume (400) in order to ensure that the outer melt surface is sealed off with oxygen, and the fluid (405), in particular the gas, preferably into the outer volume (400 ) is allowed to flow in, in particular in order to compensate for an increase in the external volume caused by the generation of a negative pressure in the casting cavity at a constant pressure. Method for die casting metal according to one of the Claims 8 to 11 , wherein a fluid (405), in particular a liquid, is introduced into the outer volume (400) in order to apply pressure to the outer melt surface and preferably at the same time to ensure that the outer melt surface is sealed off with oxygen, and the fluid (405) , especially the liquid, preferably in the outer volume (400) is pumped in to increase the external pressure acting on the outer melt surface by generating an overpressure. Method for die casting metal according to one of the Claims 8 to 12th , wherein before the melt (110) of the metal is introduced into the casting cavity, a component is inserted into the casting cavity and the component is at least partially encapsulated with the melt of the metal. Process for injection molding of plastic and die casting of metal according to Claim 13 , wherein before the component is inserted into the casting cavity, the component is at least partially encapsulated with a plastic, such that a plastic injection molded component is formed on the component, and wherein the plastic injection molded component formed on the component with the Melt of the metal is at least partially poured around, in such a way that a metal cast component is formed on the plastic injection-molded component and optionally after the plastic injection-molded component formed on the component has been at least partially poured with the melt of the metal, the metal casting -Component is in turn at least partially encapsulated with plastic, in such a way that a further plastic injection-molded component is formed on the cast metal component. Process for injection molding of plastic and die casting of metal according to Claim 14 The component inserted into the casting cavity is an electrical connector, the electrical connector comprising: one or more line elements that belong to at least one line or at least one connector, one or more shielding sleeves or shielding housings that belong to at least one line or at least one connector , and wherein the line elements of the electrical connector are at least partially encapsulated with the plastic in order to form a plastic injection molded component designed as an intermediate insulating body, which protects the line elements when the melt of the metal is poured around them, and wherein the plastic injection molded as an intermediate insulating body -Component is at least partially encapsulated with the melt of the metal in order to form a cast metal component designed as a shield housing, which either several shielding shells with one another, or at least one shielding shell with at least one shielding housing e, or connects several shielding housings to one another, or forms part of the shielding housing. Combined injection molding / die casting mold (312) with an injection cavity (300 ') for curing an injected plastic and a separate casting cavity (300) for curing a melt of a metal and preferably a further separate injection cavity (300 ") for curing an injected plastic, The size of the cavities preferably increases, so that a component is first encapsulated with plastic in the injection cavity, then encapsulated with metal in the casting cavity, and, if necessary, finally encapsulated with plastic again in the further pointed cavity.

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